Motivation and Significance

The understanding and prediction of chemical reaction processes and their interactions with fluid flow in both natural and man-made systems is a topic of high relevance to the mission of the DOE Office of Science. These interactions play important roles in many natural physical systems including the atmosphere, the oceans, as well as geological and biological systems. They are also relevant in man-made systems including chemical and industrial processing, bio-engineering, energy sciences and combustion.

One essential element of interest in these interactions is the coupling of chemistry and transport. This coupling leads to a greatly enhanced complexity, on top of the inherent challenges in the isolated chemical and transport processes, for example, in turbulent reacting flow, which is ubiquitous in many of the above systems of interest. Research into the transient coupling between chemical and flow processes in turbulent reacting flow is key to the achievement of improved understanding of these processes, and the development of predictive capabilities necessary for modeling of these systems at physically relevant length and time scales, and with requisite fidelity in chemical kinetic and transport models.

Given the unavoidable limitations in computational capabilities, we see two possible avenues for advancing our understanding of flames. These are the development and utilization of (1) efficient algorithms and software for making best use of available computational resources, and (2) advanced computational tools with embedded analysis capabilities for providing enhanced understanding of reacting flow.

In attaining the first goal of maximizing computational efficiency, we see distinct advantages in the utilization of high-order numerical schemes in conjunction with adaptive mesh refinement (AMR). As for the second goal, of using advanced tools for enhancing physical understanding of reacting flow, this can be facilitated by the use of analysis techniques such as the Computational Singular Perturbation (CSP) method. Such analyses of the coupled transport-chemical processes in flames enable clear identification of cause-and-effect relationships in reacting flow computations. They also enable automatic chemical reduction/simplification strategies, which become the foundation for Adaptive Chemistry (AC) techniques that can lead to greatly enhanced computational efficiency.